1. Field of the Invention
The present invention relates generally to apparatus for optically recording information, especially to apparatus for multiplexing such information recording in a dimension of electric field.
2. Description of the Prior Art
FIG. 6 shows a conventional optical recording system such as shown by R. A. Bartolini, Laser Kenkyu, Vol. 11, No. 8, pp 548-555. It consists of a recording laser source 1, an objective lens 6, and a disk 3 consisting of a recording medium 3a, such as a tellurium compound, and a support 3c. Information is recorded on the recording medium 3a as a pit 7.
In operation, while the disk 3 is rotated, the laser beam 1b modulated with information in the laser source 1 is focused on the recording medium 3a by the objective lens 6 to open a pit 7 by heat. Such a thermal writing system with a laser beam permits the recording of only a bit of information per pit. Consequently, the amount of information recorded per unit area of the recording medium is determined by the number of pits formed per unit area of the recording medium. In the existing laser recording system, the diameter of a laser spot is approximately one micron so that the diameter of a pit is about one micron. Consequently, the maximum recording capacity per square centimeters is 10.sup.8 bits/cm.sup.2.
In addition, the above system is unable to make a plurality of pits simultaneously on the recording medium 3a but only one at a time sequentially.